© 2015 pearson education, inc. figure 26-1 an introduction to the urinary system. kidney ureter...
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© 2015 Pearson Education, Inc.
Figure 26-1 An Introduction to the Urinary System.
Kidney
Ureter
Urinary bladder
Urethra
Organs of the Urinary System
Produces urine
Transports urinetoward theurinary bladder
Temporarily storesurine priorto urination
Conducts urine toexterior; in males,it also transports semen
Anterior viewp. 973
not in your bookCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
© 2012 Pearson Education, Inc. © 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
Figure 26-2a The Position of the Kidneys.
Adrenal gland
Diaphragm
11th and 12th ribs
Left kidney
L1 vertebra
Ureter
Inferior vena cava
Iliac crest
Aorta
Urinary bladder
Urethra
A posterior view of the trunk
Right kidney
Renal arteryand vein
ap. 974
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Figure 26-4a The Structure of the Kidney.
Ureter
Inner layer offibrous capsule
Hilum
Renal pelvis
Renal sinus
Adipose tissuein renal sinus
Renal papilla
Minor calyx
Renal pyramid
Fibrous capsule
Major calyx
Connection tominor calyx
Renal medulla
Renal columns
Renal cortex
Kidney lobe
a A diagrammatic view of a frontalsection through the left kidneyp. 976
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Figure 26-5a The Blood Supply to the Kidneys.
Interlobararteries
Interlobarveins
Corticalradiate
arteries
Corticalradiate
veins
Arcuateveins
Cortex
Medulla
Arcuatearteries
Renalartery
Renalvein
Adrenalartery
Segmentalartery
a A sectional view, showing majorarteries and veins
p. 977
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Figure 26-5b The Blood Supply to the Kidneys.
Interlobar artery
Interlobar vein
Cortical radiate artery
Cortical radiate vein
Corticalnephron
Juxtamedullarynephron
Afferentarterioles
Arcuate vein
Arcuate artery
Renalpyramid
Glomerulus
Minor calyx
b Circulation in a single kidney lobep. 977
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Figure 26-5c The Blood Supply to the Kidneys.
Renal arteryRenal vein
Segmental arteries
Interlobar arteries
Arcuate arteries
Cortical radiate arteries
Afferent arteriolesVenules
Cortical radiate veins
Arcuate veins
Interlobar veins
Efferentarteriole
GlomerulusPeritubularcapillaries
NEPHRONS
A flowchart of renal circulationcp. 977
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Figure 26-7a The Locations and Structures of Cortical and Juxtamedullary Nephrons.
Medulla
Corticalnephron
Juxtamedullarynephron
Cortex
Collectingduct
Papillaryduct
Minor calyx
Renalpapilla
The general appearance and locationof nephrons in the kidneys
ap. 979
p. 979Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
© 2012 Pearson Education, Inc. © 2015 Pearson Education, Inc.
p. 978Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
© 2012 Pearson Education, Inc.
© 2
015
Pear
son
Educ
ation
, Inc
.
© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
Figure 26-6 The Functional Anatomy of a Representative Nephron and the Collecting System (Part 1 of 2).
NEPHRON
Proximal convoluted tubule Distal convoluted tubule
• Reabsorption of water, ions,and all organic nutrients
• Secretion of ions, acids, drugs, toxins• Variable reabsorption of water, sodium ions,
and calcium ions (under hormonal control)
• Production of filtrate
Renal corpuscle
Nephron loop
Squamous cells
Cuboidal cellswith abundantmicrovilli
Mitochondria
Cuboidal cellswith few microvilli
Renaltubule
Efferent arteriole
Afferent arteriole
Glomerulus
Glomerular capsule
Capsular spaceDescending
limb ofloop begins
Ascendinglimb ofloop ends
Thickascendinglimb
Thindescending
limb
Descending limb Further reabsorptionof water
Ascending limbReabsorption ofsodium andchloride ions
Squamous cells
Low cuboidal cells
KEY
Filtrate
Water reabsorption
Variable water reabsorption
Solute reabsorptionor secretion
Variable solute reabsorption or secretionp. 978
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Figure 26-6 The Functional Anatomy of a Representative Nephron and the Collecting System (Part 2 of 2).
COLLECTING SYSTEM
KEY
Filtrate
Water reabsorption
Variable water reabsorption
Solute reabsorptionor secretion
Variable solute reabsorption or secretion
Minorcalyx
Columnar cells
• Delivery of urine to minor calyx
Papillary duct
• Variable reabsorption of waterand reabsorption or secretion ofsodium, potassium, hydrogen,and bicarbonate ions
Intercalatedcell
Principal cell
Collecting duct
p. 978
p. 980Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
© 2012 Pearson Education, Inc. © 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
Figure 26-8a The Renal Corpuscle.
Efferent arteriole
Macula densa
Afferent arteriole
Distal convolutedtubule
Juxtaglomerularcells
Juxtaglomerularcomplex
Capsularspace
Glomerularcapillary
Capsularepithelium
Visceralepithelium(podocyte)
Glomerular capsule
Proximalconvoluted
tubule
Important structural features of a renal corpuscle.ap. 981
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Figure 26-8b The Renal Corpuscle.
Pores
Podocyte
Dense layer
Capsular space
Pedicels
Fenestratedendothelium
Filtrationslits
Podocytenucleus
Capillaryendothelialcell
Mesangialcell
Capsularepithelium
RBC
This cross section through a portion ofthe glomerulus shows the components ofthe filtration membrane of the nephron.
b
Filtrationmembrane
p. 981
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Figure 26-6 The Functional Anatomy of a Representative Nephron and the Collecting System (Part 1 of 2).
NEPHRON
Proximal convoluted tubule Distal convoluted tubule
• Reabsorption of water, ions,and all organic nutrients
• Secretion of ions, acids, drugs, toxins• Variable reabsorption of water, sodium ions,
and calcium ions (under hormonal control)
• Production of filtrate
Renal corpuscle
Nephron loop
Squamous cells
Cuboidal cellswith abundantmicrovilli
Mitochondria
Cuboidal cellswith few microvilli
Renaltubule
Efferent arteriole
Afferent arteriole
Glomerulus
Glomerular capsule
Capsular spaceDescending
limb ofloop begins
Ascendinglimb ofloop ends
Thickascendinglimb
Thindescending
limb
Descending limb Further reabsorptionof water
Ascending limbReabsorption ofsodium andchloride ions
Squamous cells
Low cuboidal cells
KEY
Filtrate
Water reabsorption
Variable water reabsorption
Solute reabsorptionor secretion
Variable solute reabsorption or secretionp. 978
© 2015 Pearson Education, Inc.
Figure 26-10a Glomerular Filtration.
Podocyte
Glomerulus
Pore
Capillarylumen
Denselayer
Filtrationslit
Pedicels
Capsularspace
Filtrationmembrane
Efferentarteriole
Afferentarteriole
The glomerularfiltration membrane
a
p. 988
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Figure 26-10b Glomerular Filtration.
Factors Controlling Glomerular Filtration
The glomerular hydrostatic pressure (GHP) is the blood pressure in the glomerular capillaries.This pressure tends to push water and solute molecules out of the plasma and into the filtrate. TheGHP, which averages 50 mm Hg, is significantly higher than capillary pressures elsewhere in thesystemic circuit, because the efferent arteriole is smaller in diameter than the afferent arteriole.
The blood colloid osmotic pressure (BCOP) tends to draw water out of thefiltrate and into the plasma; it thusopposes filtration. Over the entire lengthof the glomerular capillary bed, the BCOPaverages about 25 mm Hg.
The net filtration pressure (NFP) is thenet pressure acting across the glomerularcapillaries. It represents the sum of thehydrostatic pressures and the colloidosmotic pressures. Under normalcircumstances, the net filtration pressureis approximately 10 mm Hg. This is theaverage pressure forcing water anddissolved substances out of the glomerularcapillaries and into the capsular space.
Capsular hydrostatic pressure (CsHP) opposes GHP. CsHP, which tends to pushwater and solutes out of the filtrate and intothe plasma, results from the resistance offiltrate already present in the nephron thatmust be pushed toward the renal pelvis. Thedifference between GHP and CsHP is the nethydrostatic pressure (NHP).
Filtrate incapsular
space
Solutes
Plasmaproteins
The capsular colloid osmotic pressureis usually zero because few, if any, plasmaproteins enter the capsular space.
50
25
15
10mmHg
Net filtration pressureb p. 988
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Figure 26-10b Glomerular Filtration
Net filtration pressure
Factors Controlling Glomerular Filtration
Filtrate incapsular
space
Plasmaproteins
Solutes
50
25
15
10mmHg
Capsular colloid osmoticpressure
Capsular hydrostatic pressure (CsHP)
Net filtration pressure (NFP)
Blood colloid osmotic pressure (BCOP)
Glomerular hydrostatic pressure (GHP)
© 2015 Pearson Education, Inc. p. 988
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Figure 26-12 Transport Activities at the PCT (Part 1 of 2).
Lumen containingtubular fluid
Cuboidalepithelial cells
Proximalconvoluted
tubule
Glomerulus
Distalconvolutedtubule
Glomerularcapsule
Collectingduct
Nephron loop
Urine storageand elimination
KEY
Water reabsorption
Solute reabsorption
Variable solute reabsorptionor secretionp. 993
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Figure 26-12 Transport Activities at the PCT (Part 2 of 2).
Cells ofproximalconvolutedtubule
Glucoseand otherorganicsolutes
Tubular fluid
Osmoticwaterflow
Peritubularfluid
Peritubularcapillary
KEY
Leak channel
Countertransport
Exchange pump
Cotransport
Diffusion
Reabsorption
Secretion
p. 988
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Figure 26-13a Countercurrent Multiplication and Urine Concentration (Part 2 of 2).
Cells ofthickascendinglimb
Tubular fluid
Peritubularfluid
This plasmamembrane isimpermeableto water
Urea
KEY
Cotransport
Exchange pump
Reabsorption
Secretion
Diffusion
The mechanism of sodium and chloride ion transport involves theNa+–K+/2 Cl– carrier at the apical surface and two carriers at thebasal surface of the tubular cell: a potassium–chloride cotransportpump and a sodium–potassium exchange pump. The net result isthe transport of sodium and chloride ions into the peritubular fluid.
a
p. 995Loop of Henle
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Figure 26-13b Countercurrent Multiplication and Urine Concentration.
Thindescending
limb(permeable
to water;impermeable
to solutes)
Renal medulla
Thickascending limb(impermeableto water;active solutetransport)
KEYImpermeable to water
Impermeable to solutes
Impermeable to urea;variable permeability to water
Permeable to urea
Transport of NaCl along the ascending thick limb resultsin the movement of water from the descending limb.
bp. 995
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Figure 26-13c Countercurrent Multiplication and Urine Concentration.
Thin descendinglimb (permeable
to water;Impermeable
to urea)
Renalcortex
DCT andcollectingducts(impermeableto urea;variablepermeabilityto water)
Renal medulla
Papillary duct(permeable tourea)
The permeability characteristics of both the loop and the collectingduct tend to concentrate urea in the tubular fluid and in the medulla. The nephron loop, DCT, and collecting duct are impermeable tourea. As water reabsorption occurs, the urea concentrationincreases. Papillary duct permeability to urea makes up nearlyone-third of the solutes in the deepest portions of the medulla.
c
Na+
Cl–
Urea
KEY
Impermeable to water
Impermeable to solutes
Impermeable to urea;variable permeability to water
Permeable to urea
p. 995
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Figure 26-8a The Renal Corpuscle.
Efferent arteriole
Macula densa
Afferent arteriole
Distal convolutedtubule
Juxtaglomerularcells
Juxtaglomerularcomplex
Capsularspace
Glomerularcapillary
Capsularepithelium
Visceralepithelium(podocyte)
Glomerular capsule
Proximalconvoluted
tubule
Important structural features of a renal corpuscle.ap. 988
© 2015 Pearson Education, Inc.
Figure 26-14ab Tubular Secretion and Solute Reabsorption by the DCT.
Proximalconvoluted
tubule
Glomerulus
Glomerularcapsule
Distalconvoluted
tubule
Collectingduct
Nephronloop
Urine storageand elimination
Cells ofdistalconvolutedtubule
Peritubularfluid
a
KEY
Peritubularcapillary
Tubular fluid
Sodium and chloridereabsorption along entirelength of DCT
Leak channel
Countertransport
Exchange pump
Cotransport
Diffusion
Reabsorption
SecretionAldosterone-regulated pump
The basic pattern of thereabsorption of sodium andchloride ions and the secretionof potassium ions.
b Aldosterone-regulated reabsorptionof sodium ions, linked to the passiveloss of potassium ions.
Sodium ions arereabsorbed inexchange forpotassium ions whenthese ion pumps arestimulated byaldosterone (A).
Tubular fluid
Sodium–potassium exchange inaldosterone-sensitive portion of DCTand collecting duct
p. 998 DCT
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
© 2012 Pearson Education, Inc.
p. 998 DCT© 2015 Pearson Education, Inc.
p. 998 DCT
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings© 2012 Pearson Education, Inc. © 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
Figure 26-14c Tubular Secretion and Solute Reabsorption by the DCT.
Proximalconvoluted
tubule
Glomerulus
Glomerularcapsule
Distalconvoluted
tubule
Collectingduct
Nephronloop
Urine storageand elimination
KEY
Leak channel
Countertransport
Exchange pump
Cotransport
Diffusion
Reabsorption
Secretion
Aldosterone-regulated pump
Tubular fluid
Hydrochloricacid
Ammoniumchloride
H+ secretion and HCO3– reabsorption along entire DCT and
collecting duct
Amino aciddeamination
Sodium bicarbonate
c Hydrogen ion secretion and the acidification of urine occur by tworoutes. The central theme is the exchange of hydrogen ions in thecytosol for sodium ions in the tubular fluid, and the reabsorption ofthe bicarbonate ions generated in the process.p. 999 DCT & CD
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Figure 26-15a The Effects of ADH on the DCT and Collecting Duct (Part 2 of 2).
Renal cortex
Glomerulus
PCT DCT
Solutes
Collectingduct
Renal medulla
Large volumeof dilute urine
a Tubule permeabilities and theosmotic concentration of urinewithout ADH
KEY
=Na+/Cl–
transport
=Antidiuretichormone
=Waterreabsorption
=Variable waterreabsorption
=Impermeable to solutes
= Impermeable to water
=Variable permeabilityto water
p. 1000
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Figure 26-15b The Effects of ADH on the DCT and Collecting Duct (Part 2 of 2).
KEY
=Na+/Cl–
transport
=Antidiuretichormone
=Waterreabsorption
=Variable waterreabsorption
=Impermeable to solutes
= Impermeable to water
=Variable permeabilityto water
Renal cortex
Renal medulla
Small volume ofconcentrated urine
b Tubule permeabilities and the osmoticconcentration of urine with ADH p. 1000
© 2015 Pearson Education, Inc.
Figure 26-13c Countercurrent Multiplication and Urine Concentration.
Thin descendinglimb (permeable
to water;Impermeable
to urea)
Renalcortex
DCT andcollectingducts(impermeableto urea;variablepermeabilityto water)
Renal medulla
Papillary duct(permeable tourea)
The permeability characteristics of both the loop and the collectingduct tend to concentrate urea in the tubular fluid and in the medulla. The nephron loop, DCT, and collecting duct are impermeable tourea. As water reabsorption occurs, the urea concentrationincreases. Papillary duct permeability to urea makes up nearlyone-third of the solutes in the deepest portions of the medulla.
c
Na+
Cl–
Urea
KEY
Impermeable to water
Impermeable to solutes
Impermeable to urea;variable permeability to water
Permeable to urea
p. 995 CD
© 2015 Pearson Education, Inc.
Figure 26-11 The Response to a Reduction in the GFR (Part 2 of 2).
Autoregulation
Immediate localresponse in thekidney
Increasedglomerularblood pressure
Dilation ofafferent arterioles
Contraction ofmesangial cells
Constriction ofefferent arterioles
HOMEOSTASISRESTORED
NormalGFR
HOMEOSTASISDISTURBED
Decreased GFRresulting in
decreased filtrateand urine
production
if sufficient
HOMEOSTASIS
Normalglomerular
filtration rate
Start
p. 991
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Figure 26-11 The Response to a Reduction in the GFR (Part 1 of 2).
Renin–Angiotensin-Aldosterone System
Integrated endocrine andneural mechanisms activated
Endocrineresponse
Juxtaglomerularcomplex increasesproduction of renin
Renin in the bloodstreamtriggers formation of
angiotensin I, which is thenactivated to angiotensin II by angiotensin converting
enzyme (ACE) in the capillaries of the lungs
Angiotensin II constrictsperipheral arterioles and
further constricts theefferent arterioles
Angiotensin II triggersincreased aldosterone
secretion by theadrenal glands
Angiotensin IItriggersneural
responses
Aldosteroneincreases
Na+ retention
Increased fluidconsumption
Increased fluidretention
Constriction ofvenous reservoirs
Increasedcardiac output
Together, angiotensin IIand sympathetic activation
stimulate peripheralvasoconstriction
Increasedsympatheticmotor tone
Increased ADHproduction
Increasedstimulation ofthirst centers
HOMEOSTASISRESTORED
Increasedglomerularpressure
Increasedsystemic
bloodpressure
Increasedblood
volume
HOMEOSTASIS
Normalglomerular
filtration rate p. 991
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Figure 26-16 Summary of Renal Function (Part 1 of 6).
p. 1002
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Figure 26-16 Summary of Renal Function (Part 2 of 6).
p. 1003